A novel strategy for arsenic phytoremediation

项目总结： 食物链中的砷污染是一个全球健康问题，会对大多数人体器官造成损害。 迫切需要开发解决环境砷问题的方法。长期目标是 开发以植物为基础的污染土地修复方法，具有成本效益和生态效益 作为传统补救方法的替代方案，这是一种友好的方法。这项研究的目标是开发一种 基于遗传学的植物修复策略，用于砷的吸收、转运、解毒和 超积累进入快速生长、高生物量的非粮食作物海蓬子。纳米硫化物将是 用来调节土壤中砷的生物有效性和植物提取，并增加储存容量 通过加强硫的同化作用。经过改造的Crambe将在#年接受从土壤中去除砷的评估 实验室、温室和田间条件。我们的中心假设是基因的器官特异性表达， 它们控制As的运输、氧化态和结合，可以被调节以产生有效的提取和 在地上植物组织中的超积累。为了验证我们的假设，我们提出了以下具体建议 目标。1)共表达细菌ArsC、gECS和AtABCC1的基因工程菌Crambe abyssinica 和RNAi抑制内源砷酸还原酶CaACR2；2)评价Crambe工程系 用于金属(类)的耐受和积累；3)合成并应用纳米硫来调节生物利用度， 植物提取和有毒金属(类物质)的积累；以及4)进行工程克兰贝的试验性田间研究 在受污染的场地排起了提取植物的队伍。在组织培养基加 金属，表现最好的四重基因堆叠(arcs+gecs+AtABCC1+CaACR2Ri)Crambe品系 类型控制将使用受砷污染的土壤以及温室中的混合污染物进行测试。一个 然后，将在一个被砷污染的地点进行现场规模的试点研究。土壤将被广泛地 将用电感耦合等离子体质谱、高效液相色谱-电感耦合等离子体质谱检测金属含量和砷的形态。 电感耦合等离子体质谱(ICPMS)以及XANES(X射线吸收近边光谱)。最后，使用工程土壤改良剂 纳米硫磺将用于评估对土壤结构、污染物有效性和植物提取的影响。 纳米硫磺还将被广泛应用于植物，通过增强硫磺来增加金属储存能力 同化。这一项目的预期结果是从机理上理解生物地球化学和 将关键土壤特性与植物提取效率联系起来的砷修复植物过程 和砷的过度堆积。结果将立即产生重要的积极影响，因为 这项研究产生的知识将使高效和有效的植物修复方法成为可能 尽量减少或消除食物链中的砷污染，提高公众健康。

Project Summary: Arsenic contamination in the food chain is a global health problem and causes damage to most human organs. A significant need exists to develop approaches for addressing environmental arsenic. The long term goal is to develop a plant-based phytoremediation approach for contaminated land that is cost-effective and ecologically friendly as an alternative to conventional remediation methods. The objective of this study is to develop a genetics-based phytoremediation strategy for arsenic uptake, translocation, detoxification, and hyperaccumulation into the fast-growing, high biomass, non-food crop Crambe abyssinica. Nanosulfur will be utilized to modulate the bioavailability and phytoextraction of As from soil and to increase the storage capacity via enhanced sulfur assimilation. The engineered Crambe will be evaluated for removing arsenic from the soil in laboratory, greenhouse, and field conditions. Our central hypothesis is that organ-specific expression of genes, which control the transport, oxidation state, and binding of As, can be tuned to yield efficient extraction and hyperaccumulation into above-ground plant tissues. To test our hypothesis, we propose the following specific aims. 1) Genetically engineer Crambe abyssinica lines for co-expressing bacterial ArsC, gECS, and AtABCC1 and RNAi suppression of endogenous arsenate reductase CaACR2; 2) Evaluate the engineered Crambe lines for metal(loids) tolerance and accumulation; 3) Synthesize and apply nanosulfur to modulate the bioavailability, phytoextraction, and accumulation of toxic metal(loids); and 4) Conduct a pilot field study of engineered Crambe lines for phytoextraction on a contaminated site. After initial screening in tissue culture media supplemented with metals, the best performing quadruple gene stacked (ArcS+gECS+AtABCC1+CaACR2Ri) Crambe lines with wild type controls will be tested using contaminated soils with arsenic as well as co-contaminants in greenhouse. A pilot field-scale study will then be carried out at a site contaminated with arsenic. The soil will be extensively characterized, and analysis for metal content and arsenic speciation will be determined using ICP/MS, HPLC- ICP/MS as well as XANES (X-ray Absorption Near-Edge Spectroscopy). Last, soil amendments with engineered nanosulfur will be used to evaluate the impacts on soil structure and contaminant availability and phytoextraction. Nanosulfur will also be foliarly applied to plants to increase the metal storage capacity via enhanced sulfur assimilation. The expected outcome of this project is a mechanistic understanding of the biogeochemical and plant processes of arsenic remediation that connects key soil characteristics with the efficiency of phytoextraction and hyperaccumulation of arsenic. The results will have an immediate and important positive impact because the knowledge generated from this study will enable efficient and effective phytoremediation approaches to minimize or remove arsenic contamination in the food chain and enhance public health.